Stormwater in the Yarra Ranges
Fact Sheet 2015
Rain Water Tank
Rain Garden
Advice for landowners, building surveyors, designers and plumbers
about catering for stormwater when building and extending houses
When roofs and paving replace natural vegetation, the volume and speed of
stormwater leaving a site increases greatly
The increased water flows following rain can cause flooding of properties downstream plus erosion and pollution of
streams.
Between rain storms, the creeks receive less clean, filtered water. This is the water that used to seep through the soils
now covered by roofs, driveways and paved areas.
In the past additional stormwater has been diverted into a stormwater drainage system to protect the properties
downstream. However, this does not protect the streams from erosion and pollution. Where they exist, these drainage
systems are available for residents to use.
To protect the health of the streams, residents are encouraged to install water tanks and rain gardens to slow down
and reduce the amount of stormwater leaving a site. These initiatives will also reduce the demand for water from
Melbourne’s water storages.
Water Tanks and Rain Gardens
Water Tanks and Rain Gardens are two of the components used in Water Sensitive Urban Design (WSUD). WSUD
systems are designed so that the site matches the stormwater runoff characteristics of the site prior to construction and
must meet the performance requirements of the Building Code of Australia.
Where no stormwater drainage system exists, the complete system can be built using WSUD components. Some
locations may need to use a combination of WSUD components.
WSUD components can also be used in conjunction with existing drainage infrastructure. The system should be
designed by a person experienced in Water Sensitive Urban Design (WSUD) and it is preferable that the system caters
for stormwater generated by the entire roof area and paved areas. Using WSUD components will contribute to the
health of the downstream streams and may also avoid the cost of upgrading existing drainage systems.
Council Drains
Where Council has underground drains, kerb and channel or open table drains adjacent to the low point of a property,
Council will provide residents with information about that infrastructure through a Stormwater Point of Discharge
Nearby Council Drains
There is also the option to construct private drainage to council standards so that the drain can become a council
asset. The drain would then be maintained by council. It would also be available for use by other properties.
Groups of properties can also request council to install drainage as a special charge scheme where all abutting
residents contribute to the cost of the scheme. Further information is available from Council.
Melbourne Water Drains and Streams
In some areas the stormwater can be connected to Melbourne Water drains and streams. Residents will need to
contact Melbourne Water for approval.
WSUD as well as pipes and pits
Use of WSUD components prior to connection to traditional stormwater drainage systems is encouraged and will
provide the benefits discussed on the previous page. The WSUD components will also help meet Melbourne Water,
water quality standards.
WSUD - Rain Water Tanks
Rainwater tanks (or similar) can be used to collect stormwater to enable water re-use within the property. Tank size is
likely to be 5,000 litres for every 100 square metres of roof area being captured.
Examples of water reuse within the property are connections to toilets and laundries. Captured water can also be used
to service outdoor (garden) watering demands but must be in addition to indoor use.
A planning permit from Yarra Ranges Council may be required for tanks exceeding 4,500 litres.
Existing farm dams can be used as part of the system provided the dams meet government regulations.
WSUD - Rain Gardens
Rain Gardens store and filter stormwater. The Rain Garden size can start from 8 square metres but the size will vary.
Rain Gardens should be designed to cater for the stormwater flows from roof areas and from paved areas.
Rain Gardens will need regular cleaning and weeding. New soil and rocks may be required at regular intervals.
Rain Gardens can be designed to incorporate vegetable gardens.
WSUD - Infiltration on Site
Contour drains or infiltration trenches allow water to seep into the ground. Trench lengths of twenty metres or more
may be required dependent upon soil type and the amount of stormwater being catered for.
Note - Overflow
The overflow from any WSUD treatments must not cause a nuisance or damage to any other properties.
Note - Risk of Landslip
Where properties are at risk of landslip, all water runoff should be catered for in accordance with geotechnical
guidelines. Infiltration on Site and Rain Gardens are unlikely to be appropriate. Areas having significant susceptibility
to landslip are identified and managed through the Erosion Management Overlay (EMO) of the Yarra Ranges
Planning Scheme.
For further information please contact Yarra Ranges Council on 1300 368 333 or www.yarraranges.vic.gov.au
Information about Water Sensitive Urban Design (WSUD) can be found on the Melbourne Water web sites
http://wsud.melbournewater.com.au/ and http://raingardens.melbournewater.com.au/
Applications for a Stormwater Point of Discharge can be made online at www.yarraranges.vic.gov.au via eServices
Special Charge Schemes - Contact Yarra Ranges Infrastructure Services Department
Planning Scheme and Permits - Contact Yarra Ranges Planning Department